Patent Literature 1 discloses a touch sensor system which detects distribution of values of a plurality of capacitors respectively provided at intersections of a plurality of first signal lines and a plurality of second signal lines. As shown in Patent Literature 2, a conventional touch sensor system configured to detect how capacitances are distributed has been trying to carry out recognition of a finger and part of a hand which are in contact with a touch panel by means of signal processing.
FIG. 18 is a block diagram illustrating a configuration of a conventional touch sensor system 91. The touch sensor system 91 includes a touch panel 93 and a capacitance distribution detecting circuit 92. The touch panel 93 includes drive lines HL1 to HLn provided in parallel with each other in a horizontal direction, sense lines VL1 to VLm provided in parallel with each other in a vertical direction, and a plurality of capacitors respectively provided at intersections of the drive lines HL1 to HLn and the sense lines VL1 to VLm.
The capacitance distribution detecting circuit 92 includes a driver 95. The driver 95 drives the capacitors by applying voltages to the drive lines HL1 to HLn in accordance with a code sequence. The capacitance distribution detecting circuit 92 is provided with a sense amplifier 96. The sense amplifier 96 reads out, through the sense lines VL1 to VLm, a linear sum of voltages corresponding to the capacitors driven by the driver 95, and supplies the linear sum to an AD converter 98. The AD converter 98 converts, from analogue to digital, the linear sum and supplies the linear sum thus converted to a capacitance distribution calculation section 99.
The capacitance distribution calculation section 99 calculates distribution of capacitances on the touch panel 93 on a basis of (i) the linear sum of the voltages corresponding to the capacitors, which sum has been supplied from the AD converter 98, and (ii) the code sequence, and supplies the calculated distribution of capacitances on the touch panel 93 to a touch recognition section 90. The touch recognition section 90 recognizes a touched position on the touch panel 93, on a basis of the distribution of capacitances which has been supplied from the capacitance distribution calculation section 99.
The capacitance distribution detecting circuit 92 includes a timing generator 97. The timing generator 97 generates a signal for specifying an operation of the driver 95, a signal for specifying an operation of the sense amplifier 96, and a signal for specifying an operation of the AD converter 98, and supplies the signals to the driver 95, the sense amplifier 96, and the AD converter 98, respectively.
Furthermore, there is also known a configuration in which a hand-placing region which is a region of a touch panel including a plurality of capacitors provided in a matrix manner and on which region a hand is placed in order to make an input with a stylus to the touch panel is specified by application software mounted on a host device connected with a touch sensor system, a frame indicative of the hand-placing region is drawn, and a position of the hand-placing region is changed appropriately in accordance with movement of the hand placed on the touch panel in order to make an input with the stylus.